Turntable for phonographs



Sept...l .16 1924.A

R. B. wHlTMAN TURNTABLE FCR PHONOGRAPHS Filed ec. 19'.A 1921 Patented Sept. i6, 1924.

UNTED STATES incassa PATENT foFFica.

RAY B. WHITMAN, F BRIDGEP'ORT, CONNECTICUT, ASSIGrNOR` TO COLUMBIAKPHONO- GRAPH COMPANY, INCORPORATED, 0F BRIDGEPORT, CONNECTICUT, A y('}()Il3.IOL'\,A

TION AOF NEW YORK.

TURNTABLE FO'R PHONOGRAPHS.

Application led December 19, 1921. Serial No. 523,361.

To all whom t may concern.'

Be it known that I, RAY B. VHITMAN, a citizen of the United States, and aresident of the city of Bridgeport, county of Fairfield, and State of Connecticut, have invented certain new and useful Improvefy ments in Turntables for Phonographs, of which the following, taken in connection with the accompanying drawings, is` a specification.

This invention relates to improvements in turn-tables for phonographs, and has foran object to provide a turn-table which may be made from sheet metal, and which maybe conveniently pressed. to shape and formed by a minimum of simple manufacturing operations.

Another object is to provide a turn-table, which will possess the combined characteristics of lightness, strength, and rigidity, and in which all tendency to` war or bend, due to strains, atmospheric con itions, or other causes, is entirely eliminated.

Still another object is to so strengthen and reinforce the turn-table by means of ribs formed integral with the sheet metal structure, as to resist strains along all diameters and chords of the turn-table.

A further object is to provide improved means for securely attaching the fabric covering to the upper surface by eihcient manufacturing methods, and to enclose the edge of the covering', so that it will be protected against wear and detachmentydue to rough handling. Tothis end, animproved form of flanged strengthening-rim is provided, which', in addition to its function of strengthening the turn-table vand main-l taining its flat disc-form, encloses and protects the edge of the fabric covering, as aboveA pointed out; and, furthermore, adds great attractiveness to the turn-table.k

A still fuither objectz is to prevent the transmission through the turn-table of sound generated at the record, and to eliminateall extraneous vibrations; this, in order that proper sound reproduction may obtain, without the deleterious diaphragm-effect of the turn-table.

Finally, an object is tovprovide an improved method yof forming and construct ing' the turntable, in order to produce an improved structure, and als@ economyy in manufacture. f f

With these and other objects in View, em-fbodiments ofthe invention are shown in therv accompanying drawings; and these embodiments will be hereinafter more fully described with reference thereto, and the in-` vention finally pointed out in claims.

In the drawingsn d Fig. l is a plan View of a'turn-table, according to one embodiment of the invention,

a portion of the fabric covering being re-r moved to clearly illustrate the body of the turn-tablet; f

Fig. `2 is a vertical sectional View of same. taken along the irregular line 2 2 of Figi:

Fig. 3 is an enlarged detail sectional View' of the rim portion ofthe turn-table, 'and showing the same partially bent to shape, this being the first formative step;

Fig. 4 is a similar view, andfshowing the riinflange completed, or vafter the final formative step;

t ig. 5 is a similar view, showing the fabric covering finally positioned within the rimcenter-hearing, for engaging the turn-table spindle, is attached; Y

Fig. 11 is a sectional view thereof, taken along the irregularfline 11j-ll of Fig. l0;

Fig. 12 is ay plan viewy of the completed turn-table with the fabric coveringattached; Fig. 13 is asectional View along the 'line Fig. 14; is asectional view along the linel ilieii of Figi. x

Similar reference characters indicate corresponding parts ,throughout 'the -several figures of the drawings.

Referring particularl of the drawings, the illustrative embodiment of the invention disclosed therein comprises a sheetfmetal disc 20, preferably of. steel having acenter holeQl, and a 'central de- Pressed. Q? dishes Portieri surrounding to Figs. l Land 2 f the center holeinconcentricrel-ation there.- to. A plurality of equi-spacedperforations,

vor slots is formed in the disc, these being hereshown @alternating long ,Slots andv case of their-ibs at'bothsides of the slQts,

they are only half the width l (Fig. 13).

The long slots arearrai-iged tangentially, with relation to a "circumferential line vdisposed between t-he periphery of the depressed portion and the center hole, while the short slots are radially disposed and eX- tend yacross-the -annular area surrounding the-dished portion, all of the slots extendingy in yclose proximity to the rim-flange.` The' long -slots are in rectangular relation tov-each other, theirc-ppcsedinner ends overlapping, so -that the slots and reinforcing ribs lintersect substantially levery diameter and chord of thedisc at o-nefor more points. The short radial slots are also preferably arranged at right angles to each other, as shown.

Avplurality of circular perforations 27 is provided in vt-he annular vraised-portion of the turn-table in alternatingrelation to the slots. The perforating of the turn-table and the proi'fision of thefslots and ribs prevents the transmission of sound generated at the record, breaks up the diaphragmeffect of the turn-table,and diminishes all extraneous sounds, whether generated through the vibrationso'f the-motor, transmittefd through the turn-table shaft, or yresulting from sympathetic Vibration due to the natural period of the turn-table itself.

The center-bearing for engagingthe tur-ntable spindle is secured to the under side of the dished `or depressed portion 22, land consists 'of a casting-*having a flat upperporticn-28,-and atubular central portioni29 having -atapere'd bore, lthe taper being such asfeto fit the endeof the turn-table spindle and being not-greater Ain :diameter 'at its reduced end, than is the centerhole -2l of the turn-table.

A plurality of radially-extending, equiyspaced attachment lugs orea-rs 30 (Fig. l)

are provided upon,y and formed integral with, the'flat upperport-ionl28, andare secured-to the turn-tableby mea-ns of rivets 31, counte-rsunk kat their upper ends, as clearly indicatedinfF ig. v'2 g "The lugs 30 are sca-designed' asi toexterid with-n the spaces betweenthe ends of the slnts2,3,..ai1gdyserve to increase the rigidity and strength of the turn-table structure, by providing a substantially-Continuons reinforcement, freir the center loutward'.

The strengthening of the turn.-:table is further enhanced by the formation at its outer periphery of a beaded circumferential rib 32, formed by bending the material downwardly atright angles to the surface of the turn-table, as at 33 (Figs. 2 and 3) and then upwardly and inwardly in a continuous curl, as at 3dr-the inwardly-directededge portion being spaced fromthe-portion 33, so as to provide a restricted'gslot through which the edge -o'f the fabric covering, present-ly more fullyreferred-.tm-jmay be inserted. f

As shown in Fig. 3, the'. rib is.'firstformed into a `Ll shape bya ,si-mplefstamping op- L eration; and it is then bent intolitsfi-nal bead form, as shown in Figs. 4 and, by a second stamping opera-tion, 4.the upper .surface of the rib'being prefer-ably slightlybelow the uppersurf-ace ofthe turn-table, so that the fabric covering Vwill project-substantially above this uncovered rib. y

rlChe covering for the turn-tablaconsists of an upper layer-35 of a `suitable fabricvelour, felt, or thelilre-fandl-.an underjlayer of papershellacedson both sides, andsecured by kthe shellac "to 'the -fabriic` and .the

upper surface of Vthe turn-table, and furnishing a binder therebetween. At its marginal portion, the covering isinsertedinto the tubular rib, -asshow-n in vFig. '5, .and is 'Y thereby enclosed. and protected :againstawear and the possibility .of detachment through rough handling. 4The. edge ofgtheiribTbeing directed inwardly so .as togfacetheidownwardly-extending marginal-portion of the covering, is thereby concealed sotthat..a..c0ntinuously rounded surface, entirely :free vof sharp edges, is provided.

Figs. 6 to 12 illustrate .the method .-o'f formingthe 'turn-table, according .to :the invention. A circular blank -of :sheet fsteel, or other suitable material, is ,-provided,.and in oneoperation, the rim-flange i-spressed into U-form, as atfB cuts 38to form-the slots are-provided; andthe centralaand i nular perforations 2l' and'Q? :are-:produced (See Figs. ".and 7;)

'The next step consists in. completing-the rib by Acurling theY same inwardly, as shewn enlarged in Fig. 4, Hanging. the cuts F38 1 to form the'slots with their reinforcing ribs, and depressing 1 the central dished-portion 22. (See'Figs. 8 .and i9.) Thenext step consists, as shown in Figs. lO'andl, attaching thecenterbearing for the fturntablel spindle; andthe final. step, as shown in Figl- 12,fisl to attach the 'fabriccovering Wit-h the present improvements, a .-turnjtable iS provided which maybe economically and with simple manufacturing operations, and which will possess the characteristics of strength, lightness, and yet be rigid enough to maintain its flat discform under practically all conditions.

There is illustrated and described a preferred and satisfactory embodiment of the structure and method comprising this invention, but it is obvious that certain of the novel features may be used alone or in conjunction with one or more of the other features; and that other changes may be made therein within the spirit and scope of the invention, as defined in the appended claims.

Having now described the invention, what is claimed as new, and for which Letters Patent is desired, is:

1. A turn-table for phonographs, comprising a sheet-metal disc having a plurality of perforations therein, to break up the diaphragm-effect of the turn-table.

2. A turn-table for phonographs having a plurality of flanged perforations.

3, A turn-table for phonographs, comprising a sheet-metal disc having a plurality of slots extending outwardly from the center.

4. A turn-table plate for phonographs, consisting of a disc of sheet-metal having its outer edge formed into a reinforcing rib, and its surface provided with openings to breakup the diaphragm-effect of the portion confined by the rib, the edges of the disc at the openings being reinforced to give the disc rigidity.

5. A turn-table for phonographs having a plurality of perforations extending in a di` rection outwardly from the center, and having downwardly extending flanges along their edges. y V

6. A turn-table for phonographs, comprisinga sheet-metal disc having a plurality of slots formed therein, and strengthening flanges, extending downwardly from the edges of said slots, the stren thening flanges being formed of metal disp aced in making the slots.

7. A turn-table for phonographs, comprising a sheet-metal disc having a plurality of radial slots formed therein, and flan es bent downwardly from their longitudina edges. 8. rA turn-table for phonographs,phaving a plurality of strengthening ribs disposed in intersecting relation with substantially every dimeter of the disc. n 9. A turn-table for phonographs, having a plurality of elongated slots formed therein, and having flanges extending along their longitudinal sides, and reinforcing the disc along substantially every diameter thereof.

10. A turn-table lfor honographs, comprising a sheet-metal disc, a plurality of spaced reinforcing ribs, and a center bearing for the turn-table spindle secured tothe disc, andr having radial projecting portions extending into the spaces between the ribs.

l l1. A phonograph turn-table disc of sheet material having a plurality of perforations to break up the diaphragm-effect of the turn-k table, the perforations being disposed in intersecting relation to substantially every diameter o f the disc.

Signed at Bridgeport, in the county of Fairfield, and State of Connecticut, this 16th day of December, A. D. 1921.

` RAYy B. WHITMAN. 

